posix_setgid()

(PHP 4, PHP 5, PHP 7)

Set the GID of the current process

说明

posix_setgid(int $gid): bool

Set the real group ID of the current process. This is a privileged function and needs appropriate privileges(usually root)on the system to be able to perform this function. The appropriate order of function calls is posix_setgid() first,posix_setuid() last.

Note:

If the caller is a super user, this will also set the effective group id.

参数

$gid

The group id.

返回值

成功时返回TRUE，或者在失败时返回FALSE。

范例

posix_setgid() example

This example will print out the effective group id, once it is changed.

<?php
echo 'My real group id is '.posix_getgid(); //20
posix_setgid(40);
echo 'My real group id is '.posix_getgid(); //40
echo 'My effective group id is '.posix_getegid(); //40
?>

参见

• posix_getgrgid()Return info about a group by group id
• posix_getgid()Return the real group ID of the current process

if you're going to use this along with posix_setuid, make sure you call posix_setgid first:
<?php
define (PROC_USER, 'john');
define (PROC_GRP, 'admins');
?>
following works:
<?php
$user = posix_getpwnam( PROC_USER );
$group = posix_getgrnam( PROC_GRP);
echo posix_getuid()."\n";
echo posix_getgid()."\n";
posix_setgid($group['gid']);
posix_setuid($user['uid']);
echo posix_getuid()."\n";
echo posix_getgid()."\n";
?>
following will not set gid
<?php
$user = posix_getpwnam( PROC_USER );
$group = posix_getgrnam( PROC_GRP);
echo posix_getuid()."\n";
echo posix_getgid()."\n";
posix_setuid($user['uid']);
posix_setgid($group['gid']);
echo posix_getuid()."\n";
echo posix_getgid()."\n";
?>